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Fix UB in compiler-rt base64 implementation 

As a follow-up to 1454c27b60
This commit is contained in:
serge-sans-paille 2020-03-03 13:27:36 +01:00
parent 221641be02
commit 292ab49d43
1 changed files with 4 additions and 3 deletions
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7
compiler-rt/lib/fuzzer/FuzzerUtil.cpp
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@ -161,20 +161,21 @@ std::string Base64(const Unit &U) {
size_t i = 0, j = 0;
for (size_t n = U.size() / 3 * 3; i < n; i += 3, j += 4) {
uint32_t x = (U[i] << 16) | (U[i + 1] << 8) | U[i + 2];
uint32_t x = ((unsigned char)U[i] << 16) | ((unsigned char)U[i + 1] << 8) |
(unsigned char)U[i + 2];
Buffer[j + 0] = Table[(x >> 18) & 63];
Buffer[j + 1] = Table[(x >> 12) & 63];
Buffer[j + 2] = Table[(x >> 6) & 63];
Buffer[j + 3] = Table[x & 63];
}
if (i + 1 == U.size()) {
uint32_t x = (U[i] << 16);
uint32_t x = ((unsigned char)U[i] << 16);
Buffer[j + 0] = Table[(x >> 18) & 63];
Buffer[j + 1] = Table[(x >> 12) & 63];
Buffer[j + 2] = '=';
Buffer[j + 3] = '=';
} else if (i + 2 == U.size()) {
uint32_t x = (U[i] << 16) | (U[i + 1] << 8);
uint32_t x = ((unsigned char)U[i] << 16) | ((unsigned char)U[i + 1] << 8);
Buffer[j + 0] = Table[(x >> 18) & 63];
Buffer[j + 1] = Table[(x >> 12) & 63];
Buffer[j + 2] = Table[(x >> 6) & 63];